1. Field of the Invention
The present invention relates to a retaining device, and more particularly to a retaining device for securing a heat sink to an electronic package.
2. Description of Prior Art
Electronic packages generate beat during normal operation. The heat must be removed from the electronic packages for keeping them stable. Conventionally, a retaining device secures a heat sink on an electronic package. A common retaing device comprises a retention frame and a clip. The retention frame is mounted on a printed circuit board (PCB) and surrounds the electronic package therearound. The retention frame forms a pair of ears at opposite sides thereof. The clip comprises a pressing portion pressing on the heat sink and a pair of clamping legs depending from the pressing portion. The legs each defines an opening therein for engaging with the ears of the retention frame. Thus, the heat sink is attached on the electronic package to remove heat.
However, modem high-speed electronic packages are able to process signals at unprecedented high speeds. As a result, the electronic packages can generate huge amounts of heat during operation. To keep normal operation of an electronic package and prevent the electronic package from being destroyed, the heat sink must be developed to have great heat dissipation capability. The heat sink is correspondingly heavy. Correspondingly, the retaining device is developed to be strong enough. This makes the engagement of the clip and the retention frame laborsome. Thus, tools are required to facilitate the clip to be engaged with the retention frame.
Accordingly, an object of the present invention is to provide a retaining device which easily fastens a heat sink to an electronic package without any tool.
In order to achieve the object set out above, a retaining device in accordance with a preferred embodiment of the present invention comprises a retention frame, a back plate, a clip and a wire arm. The retention frame forms a pair of protrusions at opposite sides thereof and an ear at one of said sides of the retention frame. A pair of posts extends from the back plate and further protrudes from the protrusions. The clip comprises a pressing lever and a pair of legs depending from the lever. A pair of hooks is inwardly formed from the legs for engaging with the posts. The wire arm comprises a locating portion positioned on the retention frame, a pressing portion resting on the clip and an operating portion clamped under the ear of the retention frame. The locating portion and the operating portion extend in opposite directions from the pressing portion.